Method of stabilizing fats and oils and compositions obtained thereby



Patented Jan. 12, 1954 METHOD OF STABILIZING FATS AND OILS. AND COMPOSITIONS OBTAINED THEREBY Noel H. K'uhrt, Rochester, N'. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a. corporation of New Jersey i No Drawing; Application October 26,, 1951,

Serial No. 253,469

12 Claims. v 1

Thi'sfinvention relates 'tomethods of stabilizing fats and oils and to the stabilized compositions obtained thereby.

Fatty materials such as fatty acids, animal fats 2 the technology of fats and oils and make it possible to supply consumers with improved fats and oils, and particularly edible fats and oils commonly used in the home.

and vegetable oils are normally subject to 'de'le- .5 Other objects will be apparent from the deterious eiTects of oxidation as evidenced by the scription and claims which follow. development of rancidity; flavor reversion, and These and. other objects are attained by means the like. It has been the practice to refine and of this invention which comprises washing fatty deodorize such fatty materials and to stabilize materials normally subject to oxidation, such as them with fat-soluble antioxidants such as citric l fats, including fatty acids, and fatty oils, with acid, propyl gallate, butylated hydroxy anisole solutions of glycine and phosphoric acid while and similar well-known antioxidants for fatty the fatty material is in liquid form, and separatmaterials, the antioxidants being employed alone ing the washing solution from the fatty mateor in varioussynergistic combinations. rial following the washing, the resulting washed It is desirable, however, to stabilize the fats and fatty material. having enhanced stability against oils to a greater degree than heretofore in order oxidation. If desired, a conventional fat-soluble to prolong the shelf stability of such materials antioxidant or combination of antioxidants can and lessen the necessity for refrigeration. thereafter be added to the washed fatty mate- It is accordingly an object of this invention to rial and the stability thereby further increased provide a new method of treating fatty materials beyond that obtainable with such antioxidant normally subject to oxidation to obtain. fatty alone. compositions having greatly enhanced stability The fatty compositions prepared in accordance against the deleterious effect of oxidation. with this invention consist predominantly of fatty It is also an object of this invention to provide material normally subject to oxidation. Such a new method of preparing improved fatty comfatty materials include both solid and liquid fats positions without the inclusion of said compoand fatty oils, whether natural or synthetic, and s'ition of] materials not normally used in foodp rt u arly a i al and ve a e at and fatty stuffs. oils and fat-forming fatty acids. The inven- It is a further object of this invention to protionwill find wide use in the preparation of vide fatty triglyceride compositions having sta- Stable y triglyceride c mpos tio s Such as bilities greater than were obtainable heretofore lard, eott'onseed O Soybean P t O maby convenional r cti rin-e oils, coconut oil, corn oil and the like as" well Another object of the invention is to provide a t b e atty acid comp t s Such as oleic asimple and commercially feasible method of acid, lineolic acid and similar fatty acids subpreparing edible fats and oils of improved sta- J' to oxidation. bi-lityagainst oxidati n, The washing of such fatty materials is effected Another object of the invention is to provide With the fatty materials in q i m o optia method of preparing fatty compositions not submum results and is carried out on normally solid ject toxobjectionable peroxide formation under fats molten State but not Substantially normal storage and handling conditions and yet 40 above p b y ow 95 C. for consisting predominantly of fatty materials noreither the solid fats the y Oils. At temmany subject t oxidation, peratures substantially above 90 C. as for ex- Another object of the invention is to treat fats ample at temp ratures a ove 96 r 1 0 0-, the and oils in such way that the subsequent addieffectivenessv the Washing process is eat y tion of conventional fat-soluble-antioxidantsgives redjucedi -ably. the washing is effected at a greatly improved stability as comparedt temperature not substantially lower than C. ventional t b l t techniques for best results without extended washing time, Another object of the invention is to provide temperatures or" as lowas 40 C. being considered improved th d of making' i al fats d below the desired'minimum temperature for prac- Vegetable oils t l again t oxidation, 50 tical operations in most cases. The washing time Another object of the invention is to provide Will, depend p n he temperature eml'ard and vegetable oils of greater inherent sta- D' y d W e times Of rom 3 to 4 minutes bility' against objectionable peroxide formation to about thirtyminutes' will ordinarily be suitable than that of'conventiona'llard and vegetable: oils. in the preferred temperature range from about Another object of the-invention is to advance 50(1'; to about C.-- Longer washing times are permissible and do not deleteriously affect the results but, of course, the longer times are usually less economical for commercial practice even though washing times of as much. as 4 hours or more are considered to be within the scope of the invention.

The fatty material is washed with glycine and phosphoric acid in solution, the washing solution preferably including both the glycine and phosphoric acid in a single solution although separate solutions can be employed in some cases. solvent employed must be a polar solvent which is immiscible with and does not dissolve the fatty material but which does dissolve the glycine and phosphoric acid. The solvent should not form an emulsion during the washing whereby separation following washing is complicated by emulsion formation. Water, glycerine and aqueous alcohols, such as aqueous methanol, aqueous ethanol, aqueous isopropanol and the like, have been found to be practical solvents for use in practicing this invention with water being preferred from the economic standpoint.

The glycine and phosphoric acid are desirably employed in substantially equal proportions and preferably with the phosphoric acid amounting to not more than twice the weight of glycine, although higher proportions of glycine are not undesirable but usually not necessary. The concentration of glycine, and phosphoric acid in the washing solution can be varied as desired but concentrations of about 0.01% to 0.5% by weight of each of such materials are adequate, and

higher concentrations are economically undesirable unless-the washing solution is reused. The glycine and phosphoric acid are preferably added in the form of the free acids, but materials furnishing glycine or phosphoric acid under the conditions described produce similar results and are within the scope of the invention. Thus, the glycine can be furnished by a salt of glycine, such as the sodium salt, or by a crude amino acid composition containing glycine and obtained by hydrolysis of proteinaceous matter such as soybean meal or the like; and the phosphoric acid can be added in the form of the sodium salt or similar material furnishing phosphoric acid. The washing process can be carried out in accordance with any of the well-known washing procedures I for fatty oils with suitable measures being taken for agitation or otherwise causing turbulence to ensure maximum contact between the fatty material and the washing solution.

The

Following the washing, the fatty material can be readily separated from the washing solution by settling and phase separation, sharp phase separations being readily obtained. If desired, however, centrifugation or other well-known separation processes can be employed. Substantially all of the glycine and phosphoric acid remains in the washing solution following such washing, and the washed fatty compositions can .thereafter be heated to temperatures considerably above 90 C. without deleterious effects. a

One of the most significant aspects of this invention is the great improvement in stability attained with conventional fat-soluble antioxidants when employed in compositions washed in accordance with this invention as compared to,

the stability attained with the same antioxidants in conventional compositions. 'This marked improvement is clearly shown in the data set out in Table 1 illustrating the invention. It should .be understood, however, that similarly improved results are obtained with any of the well-known -l2. Two washes with fat antioxidants or combinations thereof including such materials as the quinones and hydroquinones, organic carboxylic acids such as citric acid, ascorbic acid, tartaric acid, amino acids and the like, as well as esters and salts thereof, phenolic antioxidants such as' the alkylated hydroxy anisoles and the like, gallates, tocopherols and other similar well-known antioxidants for fatty material.

As shownin Table 1, water or glycerine washing alone does not enhance the stability of the fatty composition nor does the use of glycine or phosphoric acid alone greatly improve the stability beyond the conventional stability obtained by simple addition of usual antioxidants to unwashed fatty materials. The application of the .by agitating the cottonseed oil and the washing solution in a reactionvessel equipped with heating means for a period of about 30 minutes. The Washing solution was then separated out by phase separation and decantation. The stability was determined by the standard active oxygen method (AOM) wherein the sample is heated at 96 C. with air bubbling through the sample and the peroxide content in millimols per kilogram of fat is determined periodically. A peroxide value (P. V.) of 20 is considered the maximum permissible limit and the stability is expressed in terms of the number of hours to reach a peroxide value of 20 under the accelerated test conditions. It should be noted that a stability of 20 hours under the accelerated test conditions is equivalent to months of ordinary shelf storage.

Table 1 Antioxident added Washing treatment after washing 0.02% propyl gallate. 0.02% citric acid Water+0.l% glycine-.. Glycerine+0.l% glycme.

l0. Glycerine+0 5% HaPOi.

ll. Water+O.5% HePQim Wash.

14. One wash with glycerine+0.l% glycine +01% HaPOr.

0.02% propyl gallate.- 58

Similarly improved results are attained with Table 2 Composition Lard (control) 7 Washed lard A batch of commercial bleached oleic acid was similarly washed twice with water containing 0.1% glycine and 0.1% phosphoric acid at 60 C. The stability of the resulting washed oleic acid was 350% of the stability of the unwashed control sample.

This invention thus provides a simple but ef fective method of preparing fatty compositions consisting predominantly of fats or fatty oils, having greatly enhanced stability against objectionable peroxide formation.

The invention has been described in considerable detail with reference to certain preferred embodiments thereof but it will be understood that other fats and fatty oils can be similarly treated in accordance with the invention and that variations and modifications can be effected Within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. The method of making a stable fatty composition which comprises washing a composition consisting predominantly of fatty material normally subject to oxidation, in liquid form, with glycine and phosphoric acid in solution in a polar solvent which is immiscible with said fatty material, and separating said solution from said composition following said washing.

2. The method of making a stable fatty triglyceride composition which comprises washing a fatty triglyceride, in liquid form, at a temperature below 95 C. with a solution of glycine and phosphoric acid in a fat-immiscible polar solvent, and separating said solution from said fatty triglyceride composition following said washing.

3. The method of making a stable fatty triglyceride composition which comprises washing a fatty triglyceride, in liquid form, at a temperature of substantially 50-90 C. with a solution of glycine and phosphoric acid in a fat-immiscible polar solvent selected from the group consisting of water, aqueous alcohol and glycerine, and separating said solution from said fatty triglyceride following said Washing.

4. The method of making a fatty composition of improved stability which comprises washing a fatty composition consisting predominantly of fatty material normally subject to oxidation, in liquid form and at a temperature of substantially 5090 (3., with a solution of glycine and phosphoric acid in a fat-immiscible polar solvent selected from the group consisting of water, aqueous alcohol and glycerine, separating said solution from said fatty composition following said washing, and adding an antioxidant for fatty material to the resulting washed fatty composition.

5. The method of making a stable triglyceride oil which comprises washing a normally liquid triglyceride oil with a solution of glycine and phosphoric acid in a fat-immiscible polar solvent, said washing being efiected at a temperature not substantially lower than 50 C. and not substantially higher than 0., and thereafter separating said solution from said triglyceride oil.

6. The method of making a stable triglyceride fat which comprises washing a triglyceride fat having a melting point of less than 90 (3., in liquid form, with a solution of glycine and phosphoric acid in a fat-immiscible polar solvent, said washing being effected at a temperature not substantially lower than 50 C. and not substantially higher than 90 C., and thereafter separating said solution from said triglyceride fat.

'7. The method of making a stable triglyceride oil which comprises washing a normally liquid triglyceride oil with a solution of glycine and phosphoric acid in a fat-immiscible polar solvent selected from the class consisting of water, aqueous alcohol and glycerine, said washing being effected at a temperature not substantially lower than 50 C. and not substantially higher than 90 C., separating said solution from said triglyceride oil and thereafter adding an antioxidant for triglyceride oil to the resulting washed triglyceride oil.

8. The method of making a stable triglyceride fat which comprises washing a triglyceride fat having a melting point of less than 90 C., in liquid form, with a solution of glycine and phosphoric acid in a fat-immiscible polar solvent selected from the class consisting of water, aqueous alcohol and glycerine, said washing being efiected at a temperature not substantially lower than 50 C. and not substantially higher than 90 0., separating said solution from said triglyceride fat and thereafter adding an antioxidant for triglyceride fat to the resulting washed triglyceride fat.

9. The method of making a stable vegetable oil which comprises washing a vegetable oil with a Water solution of glycine and phosphoric acid at a temperature below C., and separating said water solution from said vegetable oil following said washing.

10. The method of stabilizing lard against oxidation which comprises washing lard with a water solution of glycine and phosphoric acid at a temperature at which said lard is molten but below 95 C'., and separating said solution from said lard following said washing.

11. The method of making a stable vegetable oil which comprises washing a vegetable oil with a water solution of glycine and phosphoric acid at a temperature not substantially lower than 50 C. and not substantially higher than 90 C., separating said water solution from said vegetable oil, and adding a fat-soluble antioxidant to the resulting washed vegetable oil.

12. The method of making a stable lard which comprises washing lard with a water solution of glycine and phosphoric acid at a temperatureat which said lard is molten but not substantially lower than 50 C. and not substantially higher than 90 CL, separating said water solution from said lard, and adding a fat-soluble antioxidant to the resulting washed lard.

NOEL H. KUHRT.

Name Date Chappell Nov. 5, 1946 Number 

1. THE METHOD OF MAKING A STABLE FATTY COMPOSITION WHICH COMPRISES WASHING A COMPOSITION CONSISTING PREDOMINANTLY OF FATTY MATERIAL NORMALLY SUBJECT TO OXIDATION, IN LIQUID FORM, WITH GLYCINE AND PHOSPHORIC ACID IN SOLUTION IN A POLAR SOLVENT WHICH IS IMMISCIBLE WITH SAID FATTY MATERIAL, AND SEPARATING SAID SOLUTION FROM SAID COMPOSITION FOLLOWING SAID WASHING. 